Laboratory dignosis Flashcards
Tumor markers: classification
o Enzymes o Tissue receptors o Oncogenes o Hormones o Antigens (largest class)
Tumor markers: enzymes
In certain tissues are found in blood plasma at higher levels when the cancer involves that tissue
(PAP- prostatic acid phosphatase)
Tumor markers: Tissue receptors
Proteins associated with the cell membrane.
Bind to hormones and growth factors, and therefore affect the rate of tumor growth.
May be measured in the blood, extracellular fluid, and tissue samples after biopsy
(E and P receptors)
Tumor markers: Oncogenes
Some tumor markers are the product of oncogenes, which are genes that are active in fetal development and trigger the growth of tumors when they are activated in mature cells
(BARC1/2)
Tumor markers: Hormones
- hormones that are normally secreted by the tissue in which the malignancy arises
- hormones produced by tissues that do not normally produce it
(ACTH ectopic production)
Tumor markers: Antigens
Largest class of tumor marker ➢ Oncofetal antigens (AFP) (protein that are present only in fetal development and in adult life in cancer)
➢ Carbohydrate antigens (Ca 15-3)
➢ Blood group antigens (Ca 19-9)
Tumor markers:
Factors that influence the quality of results
- High specifity, i.e. not detectable in benign diseases and healthy subjects (has no false positives);
- High sensitivity, i.e. detectable very early when only a few cancer cells are present (has no false negatives);
- Organ specificity (PSA);
- Correlation with the tumor stage or tumor mass;
- Responsible to treatment;
- Correlation with prognosis;
- Reliable prediction value.
Tumor markers: criteria (7)
- High specifity, i.e. not detectable in benign diseases and healthy subjects (has no false positives);
- High sensitivity, i.e. detectable very early when only a few cancer cells are present (has no false negatives);
- Organ specificity (PSA);
- Correlation with the tumor stage or tumor mass;
- Responsible to treatment;
- Correlation with prognosis;
- Reliable prediction value.
Tumor markers: Clinical use
To detect the tumor localization, size, course of development..
GI tumor markers: (3)
Liver (3)
- AFP
- AFP-L3%
Pancreas (4)
- Ca 19-9,
- CEA,
- Ca494,
- Ca242
Colorectal (3)
- CEA,
- CTC,
- Ca 19-9
Stomach (2)
- CEA,
- Ca 72-4
GI tumor markers, clinical significance. Interpretation of results.
LIVER (3)
AFP: ▪ Useful in diagnosing cancer and in monitoring its treatment, determine prognosis or detecting tumor recurrence. ▪ Detect liver cancer at early stage. ▪ Hepatocellular carcinoma. ▪ Germ cells tumors. ▪ Chronic hepatitis.
AFP-L3:
▪ New generation TM.
▪ Specific for liver cancer (hepatocellular carcinoma)
▪ Used for screening
▪ Found to be useful indicator of distant metastasis and poor prognosis for HCC.
AFP-L3%:
▪ Very specific for small HCC.
▪ AFP-L3%>35%- 100% specificity for HCC.
Gastrointestinal tumor markers, clinical significance. Interpretation of results.
PANCREAS (2)
Ca 19-9:
▪ Not used for screening
▪ Pancreatic cancer and hepatobilliary carcinoma.
▪ Is useful in monitoring recurrence or early relapse.
Carcinoembryionic antigen (CEA):
▪ Non-specific.
▪ Not used for screening.
▪ Used for monitoring of the treatment response and reoccurrence.
▪ Colorectal cancer
▪ Pancreatic carcinoma
▪ Gastric carcinoma
▪ Lung carcinoma.
Gastrointestinal tumor markers, clinical significance. Interpretation of results.
COLORECTAL (1)
Carcinoembryionic antigen (CEA): ▪ Non-specific. ▪ Not used for screening. ▪ Used for monitoring of the treatment response and reoccurrence. ▪ Colorectal cancer ▪ Pancreatic carcinoma ▪ Gastric carcinoma ▪ Lung carcinoma.
Gastrointestinal tumor markers, clinical significance. Interpretation of results.
STOMACH (1)
Carcinoembryionic antigen (CEA): ▪ Non-specific. ▪ Not used for screening. ▪ Used for monitoring of the treatment response and reoccurrence. ▪ Colorectal cancer ▪ Pancreatic carcinoma ▪ Gastric carcinoma ▪ Lung carcinoma.
Genitourinary tract tumor markers
PROSTATE (7)
- PSA
- fPSA
- CTC
- PAP
- PSMA
- PCA3
- EPCA-2